Water is critical for sustaining life. It performs essential functions within terrestrial and marine ecosystems and represents an important input into Australia's economy, particularly agriculture.

Long-term drought in many parts of Australia, together with increasing evidence of the adverse effects of increased water use on river health, has changed the way Australians regard water. Taking too much water out of Australia’s river and groundwater systems can have detrimental economic and environmental consequences. There is added pressure on the system due to climatic conditions, which affect native animal and plant populations, agricultural production and water availability for human consumption.

WATER MANAGEMENT

With the signing of the National Water Initiative (NWI) in 2004, the states and territories, along with the Australian Government, officially recognised the need to improve the co-ordination of water management, subsequent efficiency of water use and the health of Australia’s river and groundwater systems. Built on the Council of Australian Governments (COAG) framework for water reform signed in 1994, the NWI involves a range of reforms to the water industry, including improved water planning, water trading and water accounting. The Water Act 2007 (Cwlth) established the Bureau of Meteorology as the major custodian of all water related data including collection, publication and implementation of water information standards. The Murray-Darling Basin Authority was also established under this Act, making it responsible for a national focus on water management in the Murray-Darling Basin.

Water markets are an important mechanism for allocating water efficiently and contributing to NWI goals of managing water to optimise economic, social and environmental outcomes. The National Water Commission, Australian Water Market Report, 2009–10estimated that the value of transactions for traded water was almost $3 billion and involved 4,444 gigalitres (GL) of water.

WATER AVAILABILITY

Water is principally made available to society from surface water in the form of rivers, lakes, reservoirs, dams and rainwater tanks, and from underground aquifers in the form of wells and bores. As an island continent, Australia is totally dependent on precipitation (rainfall and snow) for its water supply. Because Australia is the driest inhabited continent, man-made water storage is critical in maintaining society's water supply. Recognising the connectivity between surface and groundwater resources, the NWI parties have agreed to manage connected systems as single resources.

RAINFALL

Average annual rainfall varies considerably across Australia. Large areas of the country have average annual rainfalls of 600–1,500 millimetres (mm), a range similar to most European and North American averages. However, about half of the continent experiences an average annual rainfall of less than 300 mm.

Rainfall averaged over Australia during 2011 was 705 mm, very similar to 2010 (703 mm). The observations were the highest and second highest (respectively) during the period 1990 to 2011 (graph 2.24). Map 2.25 shows rainfall totals during 2011 over Australia, while Map 2.26 shows that most areas of Australia received above average rainfall for their region during 2011.

The Southern Oscillation Index (SOI) is calculated using the air pressure difference between Tahiti and Darwin. A strongly negative SOI (below –10), is characteristic of El Niño, which is often associated with below average winter and spring rainfall over eastern Australia, and a weaker than normal monsoon in the north. A strongly positive SOI (above +10) is characteristic of La Niña, which is often associated with above average winter and spring rainfall over eastern Australia, and an earlier than normal start to the northern monsoon season, with above-average rainfall during the tropical wet season.

In 2009–10, Australia experienced a weak El Niño event (graph 2.27). The largest impact of El Niño occurred during spring, with below average rainfall levels across much of Australia. After a relatively dry winter and spring, the warmer months exhibited rainfall patterns atypical of those normally associated with El Niño, with widespread above average summer rainfall in eastern Australia.

Water use is important to quantify because it gives a baseline for the amount of water that society needs to operate, the pressures placed on natural water systems by society, and the impacts of water management decisions on society. Measuring patterns of water use is important when predicting future land use, developing policy initiatives, or when reviewing the impact of present and past practices. For example, water use patterns give an indication of where water use efficiency programs or the buy-back of water licences should be focused. An assessment of water use by industry and households enables water managers to target management tools like drought contingency programs (e.g. water restrictions). Comparing water use with the economic value generated shows which activities are generating the most economic value to society as a result of using the resource.

The ABS publication Water Account, Australia(4610.0) provides information on the flow of water from the environment into the economy, and back to the environment. It provides data on the use of water by households, businesses and governments within the economy, and water returns to the environment.

The 2009–10 water account showed that 64,076 gigalitres (GL) of water was extracted from the environment and used within the Australian economy during 2009–10. The majority of this (86%) was extracted directly from the environment by water users, while the remaining water was extracted by the Water supply, sewerage and drainage services industry and then supplied to users.

In 2009–10, the Agriculture industry was by far the largest consumer of water, accounting for 52% of total water consumption in that year. The Water supply, sewerage and drainage services industry and Household sector were the next highest (14% each), followed by the Manufacturing industry (5%).

The Agriculture industry consumed 6,987 GL of water in 2009–10. Sheep, beef cattle and grain farming had the highest consumption within the Agriculture industry, with 2,649 GL (or 38% of the industry’s consumption). An estimated 2% (126 GL) of total agricultural water use was actually re-use water. Nursery and floriculture production consumed the highest percentage of re-use water at 7% of their total water consumption, followed by Mushroom and vegetable growing at 3% of their total water consumption.

The Mining industry accounted for 4% (489 GL) of water consumption by Australian industry in 2009–10, with Metal ore mining consuming the greatest amount (298 GL or 61%) of the water consumed by this industry.

In 2009–10, the Electricity, gas, water and waste services industry was the largest extractor of water from the environment, taking 49,793 GL. However, because 99.7% of this is in-stream use for hydro-electric power generation, the industries only actually consumed 297 GL or 2% of Australia's total water consumption.

Total water consumption in Australia fell by 28% between 2004–05 and 2009–10, from 18,767 GL to 13,476 GL, with household water consumption falling by 11% to 1,868 GL over the same time period. The decline in water consumption over this time period is indicative of reduced rainfall and drought conditions affecting water availability, particularly in southern and eastern parts of Australia.

In 2008–09, there was a large difference in the average amount paid for supplied water by different parts of the economy – households on average paid $1.93 per 1,000 litres (kL) and agricultural businesses $0.12 per kL.

AGRICULTURAL WATER USE FOR IRRIGATION

Less than 1% of the 399 million hectares of Australia's agricultural land was irrigated in 2009–10. However, of all water used for agricultural production, 90% was used for irrigation of crops and pastures. The remainder was used for other agricultural purposes, such as stock drinking water, dairy and piggery cleaning.

Agricultural water use for irrigation rose in 2009–10 by 1.5% to 6,596 GL (graph 2.28). However, the area irrigated increased by 5% to 1.84 million hectares. As a result, the average application rate decreased from 3.7 ML/ha to 3.6 ML/ha.

Pasture for grazing accounted for the greatest amount of irrigated land (542,121 hectares) in Australia in 2009–10, with the volume of irrigation water applied representing 26% of the total water used for irrigation.

There was an increase of 2.1% in the amount of water used for irrigation in the Murray-Darling Basin between 2008–09 and 2009–10 (table 2.29). The amount of water used for irrigation in the rest of Australia also rose slightly (0.8%). In total, the amount of water used for irrigation in Australia increased by 95 GL, or 1.5%, between 2008–09 and 2009–10.

2.29 AGRICULTURE WATER USE FOR IRRIGATION, Australia and Murray-Darling Basin

While there was a 1.5% increase in the amount of water used for irrigation between 2008–09 and 2009–10 in Australia, some states and territories recorded increased use of irrigation water, while others recorded a decrease (table 2.30). Victoria used a total of 1,505 GL, a 26% increase from the previous year, while Western Australia recorded an increase of 11% to 252 GL. Queensland’s use of irrigation water dropped by 235 GL (or 11%).

New South Wales used more water for irrigation than any other state or territory in 2009–10, with 30% (or 2,003 GL) of the total Australian irrigation water used.

Graph 2.31 shows water use by agricultural activity for the years 2006–07 to 2009–10. Pastures and cereal crops, together, were by far the largest consumer of water, followed by sugar and cotton.

In 2009–10, the gross value of irrigated agricultural production was $11.5 billion, an increase of 9% from 2004–05. Vegetables for human consumption was the greatest contributor (21%) at $2.4 billion, followed closely by Fruit and nuts (20%) at $2.2 billion and Dairy production (16%) at $1.8 billion. Irrigated agricultural production contributed 29% of the total gross value of agricultural commodities produced in 2009–10.

More information on irrigation in agriculture can be found in chapter 16 AGRICULTURE.

Statistics contained in the Year Book are the most recent available at the time of preparation. In many cases, the ABS website and the websites of other organisations provide access to more recent data. Each Year Book table or graph and the bibliography at the end of each chapter provides hyperlinks to the most up to date data release where available.